Survey.

Let me begin by listing some of the interfaces available in the
JDK, the methods they define, and a few comments. The basic Java
class libraries define over 3000 classes, and hundreds of
interfaces, so this list is far from compete.

A class can have more than
one of these. Access to T fields can be gained using t, t1
and t2 references.
An instance of this class can be used effectively as a
parameter to sort in the packages Arrays and Collections:public static
<T> void sort​(
List<T> list,
Comparator<? super T> c)

Enumeration

boolean
hasMoreElements()
E nextElement()

java.util

Use:

// v is an enumberable class, such as Vectorfor (Enumeration e = v.elements() ; e.hasMoreElements() ;) { System.out.println(e.nextElement());} // end for each element